Radio receiving device



June 24, 1930. w. F. LUHNOW RADIO RECEIVING DEVICE Filed March 12, 1928 3 Sheets-Sheet l June 24, 1930. w. F. LUHNOW 1,765,731

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June 24, 1930. w. F. LUHNOW 1,765,731

RADIO RECEIVING DEVICE Filed March 12, 1928 3 Sheets-Sheet 3 M M. 5 gg 1 9% JV (Ra/(3.-

Patented June 24, 1930 PATENT OFFICE WALTER I. LUHNOW, OF GREELEY, COLORADO RADIO RECEIVING DEVICE Application filed March 12, 1928. Serial No. 261,114.

This invention relates to the intensity control of wave force ranging from the lower audio frequencies upward; and more especially to the amplification of such force in the various arts dependent thereon, including radio sending and receiving, electro-phonographic recording and reproduction, public address and carrier systems, vitaphone systems and the like, telephone repeater and relay systems, and television.

The main objects of the invention are to improve the operation of audio frequency devices and to enhance their permanence and operating stability; to provide new and im- 16 proved means to accomplish these ends; to provide in devices of this sort which are adapted to amplify the Wave energy, means for equalizing and stabilizing the Wave energy within the effective range and capacity of the devices referred to; to provide especially against surging in such devices; to provide means adapted and arranged to prevent and minimize aging and the effects of aging which usually occur in transformers and cored inductance coils; to provide an improved form of coil adapted to serve as an anti-surge coil and impedance equalizer; to provide a multiplex impedance device in which a series of winding units, more or less,

may be assembled on a common magnetic core; to provide in a radio receiving set means to accomplish the objects stated; to provide impedance means such as herein indicated, adapted for ready use both in new construction work and in making'repairs and improvements on old work; and to provide efficiently for accomplishing these and other purposes, as hereinafter more fully pomted out.

An illustrative embodiment of this inyention is shown by the accompanying drawings in which:

Figure 1 is a conventional circuit diagram of a radio receiving set showing the arrangement and connection of the several members employed in the device and their relation to one another.

Fig. 2 shows diagrammatically that part of a receiving set which includes one of several embodiments of this invention, reference being had es ecially to the impedance members WhlCh in 1 are broadly represented conventionally rectangles.

Fig. 3 shows a. modification relative to F 1g. 2.

Fig. 4 shows a modification relative to Figs. 2 and 3.

Fig. 5 shows a further modification of the impedance device.

Fig. 6 shows a composite or multiplex impedance device in which a plurality of serially connected impedance units are assembled in an elongated common core.

Flg. 7 is mainly similar. to Fig. 6 exce t that the impedance units are not electrical y connected together.

Fig. 8 illustrates how the impedance units may be mechanically arranged closely in axial alinement on a common core.

Fig. 9 shows how the impedance units may be closely arranged side by side on a folded common core. Fig. 10 shows a side view of a flattened impedance helix enclosed in a copper sheath secondary, the latter being in longitudinal section.

Fig. 11 is an end view of the device of Fig. 10.

Fig. 12 is a top view of the device of Fig. 10. the sheath being in section.

Fig. 13 is an end elevation of an impedance unit such as shown in the left-hand part of Fig 2.

- ig. 14 is a longitudinal section on the line 14-44 of Fig. 13.

Referring more in detail to the drawings, and especially to Figure 1, the aerial 1 is connected in series with the inductance primary 2 and the variable condenser 3 to the ground 4. The inductance 2 transfers the radio frequency energy to the inductance secondary 5 which is tuned by the variable condenser 6.

The tube 7 has its grid 8 connected through the primary coil 9 of the air core transformer 10 to one side of coil 5. The filament 11 of said tube is connected on one side through the C battery 12 to the other side of coil 5. The other side of said filament is connected through the B battery 13 to one end of an impedance unit 14. Said filament is fed by the A battery 15 through rheostat 15. The

plate 16 of said tube is connected through the secondary coil 17 of transformer to the primary coil 18 of the iron core transformer 19, and thence to the other side of said impedance unit 14.

The secondary coil 20 of transformer 19 is connected on one side to the primary coil 21 of the iron core transformer 22 and thence to the grid 23 of the next stage tube 24; and on its other side said coil 20 is connected to another impedance unit 25 and thence through the C battery to the filament 26. The plate 27 of tube 24 is connected throu h the secondary coil 28 to the primary of t e iron core transformer 29, which is similar to transformer 19, and thence to still another impedance unit 30. Filament 26 is connected through the B battery to the other side of unit 30.

The secondary of transformer 29 is connected through the primary of transformer 31, which is similar to transformer 22,to the grid of the next tube 32; and the other side of said secondary is connected through another impedance unit 33 to the C battery and thence to the filament of tube 32.

The secondary of transformer 31 is connected to the tip of the socket switch or jack 34. The sleeve of said jack is connected through still another impedance unit 35 to the B battery and thence to the other side of the filament of tube 32. From jack 34 the circuit leads through a plug 36 and 35 cord 37 to a magnetic sound reproducer 38 having a horn or loud speaker attachment 39.

Referring further to Fig. 1, it is to be understood that the stage represented by tube 24 may be omitted and that on the other 40 hand more such stages mi ht be inserted up to the capacity of the tu s used; for 1nstance, the set might range from one to six stages.

The impedance units, wherein my lnven 68 tion mainly resides and which are indicated by numerals 14, 25, 30, 33 and 35 in Fig. 1, will now be described and explained. It is to be understood that the function of these units is merely to improve the operation of the device wherein they are used and that any or all of those shown in Fig. 1 might be omitted without rendering the set inoperative. I find that they function best when arranged as shown, but they may be inserted above the transformers 19 and 22 instead of below if desired. Moreover I find that if only one of these units is to be used, it serves best in the grid circuit, as for instance, it 1s better to omit unit 14 and retain unit 25, as in M Fig. 3, rather than vice versa. Moreover these units may be variously constructed and arranged within the scope and purpose of my invention as indicated by Figs. 2 to 11.

Referring now to Fig. 2, the plate impedance unit 51 comprises a laminated core 52,

an inner winding 53 embraced by the back turned ends of the laminations and a series outer winding 54. The grid impedance unit 56 is similar except that it includes also an inside inherently closed circuit low resistance secondary 57 It is substantially immaterial in effect, whether the inner and outer coils 53 and 54 are wound in the same or opposite directions, and whether coil 53 or coil 57 is disposed innermost.

More specifically the core 52 may well consist of sheet iron plates. but there is no essential reason why it should not consist of iron Wires or a combination of plates and wires.

A practical and convenient method of forming such a unit is to assemble a plurality of sheet metal core strips, for instance three, and then apply a winding thereto, medially of the core length; then fold or bend the ends of the two outer core strips divergently and thence backward convergently over said Winding, and overlapping each other; and finally, continue with applying another Winding outside thereof concentric with the inner Winding. The inner and outer windings may be wound continuously or they may be wound electrically independent and then connected in series to constitute an electrically continuous double coil winding. This unit should then be protected by a winding of tape or other housing material. If an inherently short-circuited winding also be desired for the unit, this is applied directly to the core before either of the above mentioned coils is applied.

In Fig. 4 the impedance units 51 and 56 are like those in Fig. 2, both in arrangement and structure. except that the core part 60 is extended so as to be common to both units, though it has short end portions 61 to embrace the inner windings 53 (see Fig. 7).

In Fig. 5 the impedance is simplified to a plain flattened copper helix 65 with a copper sleath secondary 66 such as shown by Fig.

Fig. 6 is designed to show more structural detail and to illustrate a good arrangement When a plurality of units are arranged in juxtaposition. all being connected together in series in this instance. Here we have 3 units 56 all in structure and operative effect substantially like that of Fig. 3 and all on a common core center 70. I call this combination a series triplex anti-surge unit. The inner windings may be wound all in the same direction. as preferred, so that the field direction is always the same for all of the units at any given time, but this is not essential for etfective anti-surge control.

Fig. 7 indicates the structure for a pair of units 51 and 56 on a common core center Fig. 8 shows how the units such as 51 or 56 may be assembled closely on a straight common core 60.

strips about ,(fi'to wide and appropriate lengths to make a unit about to 1" long.

When two or. more units are to be joined by a. single core, I find that one long common strip and .two short strips of iron for each unit are suliicient. When independent units are desired, two short strips sufiice for the core. For winding, I prefer No. 30 gage enameled copper wire, using 10 turns for the inner. winding and 25 turns for the outer winding. For the closed circuit secondary, I use No. 24 gage sheet copper with the edges overlappedand sweated or I may use sections of. flattened copper tubing of appropriate size. I wrap these units with tape.

Although for the purpose of description and illustration I have specifically mentioned sheet iron as a preferred core material, it is to be understood that I have no intention to limit the construction necessarily to such material, as inanifestly soft iron wires might readily be used; such. for instance, as have been used. in the making of so-called hedge hog transformers. (See pages 495 and of Alternating Currents and Alternatmg Current Machinery by D. C. and J. P. Jackson, 1902) The inherently closed circuit sec-- ondary member 66 of Figs. 10, 11 and 12. consists preferably of a section of flattened copper tubing in which the stretched out and flattened coil 66 is housed.

Referring again to Fig. 1. itis to be understood that any style or combination of these units maybe used to meet specific needs. I find them especially useful in repair work and maintenance. but for greater cfliciency, they should be installed initially.

These anti-surge coils or combinations thereof serve as compensating impedance equalizers which also prevent remodulation through the common battery as by shifting the phase of any extra strong signal or reaction or resonant point of the transformer. any one ofwhich may be due to resonance.

I find that these impedance units serve to prevent or overcome the aging of transformers or the effects thereof and have especially retarding effect with reference to deterioration.

A very special advantage, incident to using these units, is in improving the purity of tones and more ready tuning. 'lhey render available in reproduction a higher treble and a lower bass. They remove speech distortion 'sounds, as in s,

and insure clca'r reproduction of the aspirate apt, c, g, etc- .Uthough but a certain few specific embodiments of this invention are herein shown and described. it is to be understood that numerous details of the constructions shown may be altered or omitted without departing from the spirit of this invention by the following claims:

I claim: v I a. 1. Iiran electric'wave controlling system an impedance device comprising a'inagnet-ic core in combination with an inhereutlyclosed as defined circuit winding to serve reactively as an inductive impedance and another winding an impedance device comprising a. laminated core in combination with an inherently closed circuit low resistance winding and :another winding ofrelatively high resistance connected in the system, the latter winding-includi'ng two serially connected and radially spaced sect-ions, said core including laminations having their ends folded divergently and backward ly between said sections-and in themselves serving as a'core for the outer said coil section. I i 7 In an electric wave controlling system, an impedance device comprising a. windin including two serially connected and radially spaced substantially coaxial sections, in combination with closed magnetic core -means, part of which extends through said coils and part of which is disposed between said coils.

4. In a device of the clas described, an impedance member comprising a core having a. substantially closed magnetic circuit in combination with windings thereon including an inherently closed circuit low resistance winding and another winding including two radially spaced substantially concentric sections, said core having a part disposed between said sections and said low resistance winding being disposed in close inductive relation to oneof said sections.

5. In a device of the character described, a multiplex impedance member comprising a common elongated magnetic core in comhination with a plurality of impedance winding units arranged in longitudinal order thereon and electrically connected, each of said units including a winding which comprises a pair of concentrically spaced sec 1 both substantially concentric withsaidcore,

a-multiplex impedance member comprising a common elongated magnetic core in combination with a plurality of impedance winding units arranged in longitudinal order thereon and electrically connected, each of said units including a low resistance inherently closed circuit winding and a winding of relatively high resistance, the latter comprising a pair of concentrically spaced sections, and said core including parts disposed lengthwise of said member in registry with said units respectively and extending between the said sections of corresponding windings, said closed circuit winding being arranged to serve as a secondary to one of said'sections.

7. In a radio receiving set an impedance device com rising a common elongated iron core in com ination with a plurality of winding units arranged in longitudinal order thereon, each of said units including a winding which comprises a pair of mutually spaced sections; and said core, which is laminated, including short laminations arranged in registry with said units res ectively and having their ends disposed tween said sections.

8. An electric wave controlling device for radio receivers comprising an impedance unit including an iron core incombination with a winding thereon which includes two serially connected sections, said core being formed and arranged with infolded end members between said sections to provide a closed magnetic circuit for one of said sections and an open magnetic circuit for the other of said sections.

Signed at Chicago this 9th day of January, 1928.

- WALTER F. LUHNOW. 

